dmaengine: idxd: Allow ATS disable update only for configurable devices

ATS disable status in a WQ is read-only if the device is not configurable.
This change ensures that the ATS disable attribute can be modified via
sysfs only on configurable devices.

Fixes: 92de5fa2

 ("dmaengine: idxd: add ATS disable knob for work queues")
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20230811012635.535413-1-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>